The Endocrine System

Question 0

What is the difference between the endocrine system and the nervous system?

Answer 0

The nervous system regulates the activity of muscles and glands via electrochemical impulses delivered by neuron’s and those organs respond within milliseconds. The endocrine system influences metabolic activity by means of hormones which are chemical messengers released into the blood to be transported throughout the body.

Question 1

What does the endocrine system do?

Answer 1

It interacts with the nervous system to coordinate and integrate the activity of body cells.

Question 2

What are the major processes controlled and integrated by the endocrine system?

Answer 2

Reproduction; growth and development, Maintenance; of electrolytes, water,nutrient balance, and Mobilization of body defenses.

Question 3

What is endocrinology?

Answer 3

The scientific study of hormones and endocrine organs

Question 4

What are endocrine glands?

Answer 4

Also known as ductless glands they produce hormones and lack ducts, they typically have a rich vascular and lymphatic drainage that receives their hormones, as most are usually arranged in chords and branching networks.

Question 5

What do the endocrine glands include?

Answer 5

The pituitary,thyroid,parathyroid, adrenal,and pineal glands.

Question 6

What is the hypothalamus in the endocrine system?

Answer 6

It is a neuroendocrine organ, as it performs its neural functions in addition to the production and release of hormones.

Question 7

What are hormones?

Answer 7

Long distance chemical signals that travel in the lymph or blood of the body and regulate the metabolic function of other cells within the body.

Question 8

What are autocrines?

Answer 8

Chemicals that exert their effects on the same cells that secrete them.

Question 9

What are paracrines?

Answer 9

They act locally but affect cell types other than those releasing the paracrine chemicals.

Question 10

Give me an example of a homeostatic imbalance of the endocrine system

Answer 10

In certain Cancer tumor cells synthesize hormones identical to those made in the normal endocrine glands and lead to uncontrolled secretion that could lead to problems due to hormone-mediated pathology

Question 11

Hormones can be classified by ?

Answer 11

Either amino acid based in which the vary in sizes of amino acid derivatives, to peptides, and proteins or steroids which are synthesized from cholesterol in which only gonadal and adrenocortical hormones are steroids

Question 12

A given hormone influences the activity of only certain tissue cells referred to as target cells by altering their cellular activity.

Answer 12

True

Question 13

Hormones can typically produce one or more of the following changes, what are they?

Answer 13

1) alters plasma membrane permeability or membrane potential, or both,by opening or closing the ion channels. 2) stimulates the synthesis of proteins or regulatory molecules such as enzymes within the cell. 3) activates or deactivates enzymes. 4) induces secretory activity 5) stimulates mitosis.

Question 14

What is the difference between water soluble and lipid soluble hormones?

Answer 14

Water soluble hormones typically act on receptors in the plasma membrane and lipid soluble hormones act on intracellular receptors within the cell. Keep in mind there are exceptions.

Question 15

How does the cyclic AMP signaling mechanism work?

Answer 15

1) The hormone acting as the first messenger binds to its receptor on the plasma membrane. 2)binding causes activation of the G protein when GDP is displaced by GTP acting like a switch. 3) G protein binds to adenylate cyclase enzyme where it is hydrolyzed and deactivates the G protien. 4) For as long as cyclase generates a second messenger cAMP from ATP. 5) cAMP activates protein kinase which activates some proteins and inhibits others.

Question 16

What enzyme degrades cAMP?

Answer 16

Phosphodiesterase

Question 17

What signaling mechanism does oxytocin use? And how does it work.

Answer 17

PIP2 The PIP two – calcium signaling mechanism involves a G protein and a membrane bound to factor in this case an enzyme called phospholipase C then splits PIP2 phospholipid into diacylglycerol DAG then into inositol triphosphate. Like DAG cAMP activate a protein kinase enzyme which triggers responses within the target cell where IP3 releases calcium from intracellular storage sites. By directly altering the activity of specific enzymes and channels or by binding directly to calmodulin.

Question 18

In order for a target cell to respond to a hormone the cell must have a specific protein receptors on its plasma membrane or in its interior to which that hormone can bind

Answer 18

True

Question 19

Although binding of the hormone to the receptor is is the crucial first step. What are the three factors that are equally important in the activation by the hormone receptor.

Answer 19

1) blood levels of the hormone
2) relative number of receptors for that hormone on or in the target cells
3) affinity (strength) of the binding between the hormone and the receptor

Question 20

What is up-regulation?

Answer 20

When the target cell form more receptors in response to rising blood levels of the specific hormone

Question 21

Down regulation involves the loss of receptors due to desensitization of the target cells preventing it from over reaction to the persistently high hormone

Answer 21

True

Question 22

What are the types of hormone interactions at target cells?

Answer 22

There are three types of interactions which are as follows; (1) Permissiveness - is the situation when one hormone cannot exert its full effectiveness without another hormone being present. (2) Synergism- hormones occurs in situations where more than one hormone produces the same effects at the target cell and their combined effects are amplified. 3) Antagonism- may compete for the same receptors, acting through different metabolic pathways.

Question 23

What are the three types of stimuli that trigger endocrine glands to manufacture and release thier hormones

Answer 23

Humoral,neural, and hormonal stimuli

Question 24

What is a humoral stimuli?

Answer 24

Endocrine glands that secrete their hormones in direct response to changing blood levels of certain critical ions and nutrient.

Question 25

What is neutral stimulus

Answer 25

Nerve fibers that stimulate hormone release

Question 26

What is hormonal stimuli

Answer 26

Endocrine glands release their hormones in response to hormones produced by other endocrine glands

Question 27

The nervous system cannot modify both turn on factors and turn off factors that affect the endocrine system

Answer 27

False

Question 28

The pituitary gland is composed of how many lobes named them

Answer 28

Posterior pituitary gland and the anterior pituitary gland

Question 29

What are the steps in which the humoral stimuli occur

Answer 29

hypothalamus secretes hormones that stimulate the anterior pituitary gland to secrete hormones stimulate other endocrine glands that secrete hormones.

Question 30

How does oxytocin get secreted into the blood?

Answer 30

The hypothalamus synthesizes oxytocin, where it is then transported along the hypothalamic hypophsyseal tract of the posterior pituitary gland. It is then stored in the axon terminals and released into the blood when hypothalamic neurons fire.

Question 31

Which lobe of the pituitary gland is actually a part of the brain?

Answer 31

Posterior

Question 32

The anterior lobe has a direct vascular connection made of the primary capillary plexus and the secondary capillary plexus which make up the hypophsyseal portal system.

Answer 32

True

Question 33

What is the hypophsyseal portal system?

Answer 33

The portal system is an unusual arrangement of blood vessels and which capillary bed feeds into veins which in turn feed into another capillary bed. Via this portal system, releasing and inhibiting hormones secreted by neurons in the ventral hypothalamus circulate to the anterior pituitary where they regulate secretion of its hormones.